1. Field of the Invention
The invention relates to a process and apparatus for producing a geometric air projection and containment space and is particularly directed to a process and apparatus for generating such a containment space in and around an opening in a building, or the like, to prevent or minimize ingress or egress of air through said opening.
2. Prior Art
With the advent of drive-in windows at fast-food restaurants, banks, and the like, there is a need in the art for means whereby articles such as food, money, and the like, can be passed into and out of the building from a waiting car without the operator in the building being exposed to the ambient outside air.
It has been proposed heretofore to maintain openings in buildings without doors or other closures by means of a sheet of hot air acting as a screen across the opening. Similarly, it has been proposed heretofore to separate refrigerated areas in stores and shopping areas by a like screen of cold air. To be effective in these cases, the air must be hot in one case and cold in the other and, means must be provided for recovering the hot or cold air to prevent its being dissipated into the ambient.